How can I do DNS lookup in Go?
Go’s "net" package in the stdlib has standard DNS client functions.
For example, given a domain name, you can look up IP addresses:
package main
import (
"net"
"fmt"
"os"
)
func main() {
ips, err := net.LookupIP("google.com")
if err != nil {
fmt.Fprintf(os.Stderr, "Could not get IPs: %v\n", err)
os.Exit(1)
}
for _, ip := range ips {
fmt.Printf("google.com. IN A %s\n", ip.String())
}
}
Go’s stdlib either uses the C stdlib (via cgo), or a pure Go DNS resolver. On my machine, it uses cgo, which you can see with:
$ GODEBUG=netdns=9 go run main.go
go package net: using cgo DNS resolver
go package net: hostLookupOrder(google.com) = cgo
google.com. IN A 216.58.204.46
google.com. IN A 2a00:1450:4009:80d::200e
Tagged . All content copyright James Fisher 2017. This post is not associated with my employer.
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